The chemistry of terpenes. Part XX. Autoxidation of (+)-car-3-ene

Abstract

Autoxidation of (+)-car-3-ene in the presence or in the absence of cobalt stearate affords the following compounds, their yields being dependent upon the method of decomposition of the initial hydroperoxides: (+)-3α,4α-epoxycarane, (–)-8-methoxy-m-mentha-4,6-diene, (–)-car-4-en-3α-ol, (–)-8-methoxy-p-mentha-1,5-diene, eucarvone, (–)-car-4-en-3β-ol, (+)-cis-caran-5β-ol, (+)-car-2-en-4-one, (–)-m-mentha-4,6-dien-8-ol, (+)-p-mentha-1,5-dien-8-ol, 3,6,6-trimethylcyclohepta-2,4-dienone, (+)-car-3-en-2-one, 8-hydroxy-m- and -p-cymenes, and (–)-car-3-en-5-one, in this order of elution from a Carbowax g.l.c. column. A reaction sequence is suggested. Reaction of (+)-car-3-ene with selenium dioxide in pyridine gives (+)-p-mentha-1,5-dien-8-ol as the major product.